Brass Ball Valve Sizes Explained: 1/2" to 2" (15 mm to 50 mm)
Dealers and plumbers ask for ball valves in inches, while pipes are often sold in millimetres. This guide shows how the two match, where each size is often used, and what to check before you order.
Inch, DN and mm at a glance
- 1/2" = DN15 (15 mm)
- 3/4" = DN20 (20 mm)
- 1" = DN25 (25 mm)
- 1-1/4" = DN32 (32 mm)
- 1-1/2" = DN40 (40 mm)
- 2" = DN50 (50 mm)
M-Tech forged brass ball valves come in all six sizes, from 1/2" to 2". We do not make 1/4" or 3/8" ball valves.
Where each size is often used
1/2" and 3/4": branch lines to taps, bathrooms and kitchens. 1": the main inlet of a flat or a small building. 1-1/4" and 1-1/2": risers and pump lines. 2": main headers and tank outlets. Always follow the size of the pipe already fitted.
Match the valve to the pipe
Choose the same size as the pipe. A valve smaller than the pipe narrows the line and reduces flow; a bigger one needs reducers, which add joints that can leak.
Check the thread
M-Tech ball valves are threaded to the IS 554 / BS 21 / ISO 7 pipe thread standard, so they fit standard threaded pipes and fittings. Read more in our guide IS 554 vs BS 21 pipe threads.
What stays the same in every size
A forged brass body, a hard chrome-plated ball, PTFE seats and a quarter-turn lever: one short turn opens or closes the line. Every valve is tested at 350 PSI shell pressure; see what a 350 PSI shell test means. The ball valve is suitable for water, oil, air, gases and steam up to 220°C.
Need help choosing?
Send the pipe size and the line it is for on WhatsApp at +91 77550 01116, or visit www.m-techvalves.com. Forged Brass • Made in Jamnagar.